Giant American bullfrogs are culled to stop ponds takeover

A cull of giant American bullfrogs in Sussex is stopping them from destroying Britain's own smaller species.

A cull of giant American bullfrogs in Sussex is stopping them from destroying Britain's own smaller species.

The bullies of the frog world, up to 8in long, crossed the Atlantic either as exotic pets or as chance tadpole or egg arrivals with aquarium fish. In the past year, more than 7,000 froglets and tadpoles, as well as a handful of adults, have been humanely destroyed, the journal British Wildlife.reports.

The bullfrog - or Rana catesbeiana - has also been introduced into other parts of the world to produce frogs' legs for the restaurant trade. The bullfrogs are aggressive, prey on other species of frogs and may carry virulent viruses lethal to other native species. Their tadpoles are bigger, reducing the survival chances of those from other species, and they also devour insects, fish, small mammals and even small birds, anything they can get their jaws around.

There had been reports of the bellowing amphibians, usually individuals, at various sites during the 1990s. Then last year ponds in East Sussex, where a couple of adults were shot in 1996 and 1997, were found to contain big tadpoles turning into big green froglets.

The invading bullfrogs are generally pale green and have a characteristic call. Froglets often squawk when surprised.